What is the Difference Between Molecular Orbital and Atomic Orbital?

The main difference between molecular orbitals and atomic orbitals lies in the scope of the electron density they represent.

Atomic Orbitals:

1. Represent electron density associated with a particular atom.
2. Extend over one atom.
3. Describe the wave-like behavior of an electron in an atom.

Molecular Orbitals:

1. Represent electron density associated with the entire molecule, meaning the electron density is delocalized (spread out) over more than one atom.
2. Extend over more than one atom.
3. Describe the wave-like behavior of an electron in a molecule.

Both atomic and molecular orbitals share some similarities, such as being filled from lowest energy to highest energy (Aufbau principle) and being able to hold a maximum of two electrons of opposite spin per orbital (Pauli exclusion principle). Molecular orbitals are constructed using linear combinations of atomic orbitals (LCAOs), which are the mathematical sums and differences of wave functions that describe overlapping atomic orbitals.

Comparative Table: Molecular Orbital vs Atomic Orbital

The main difference between molecular orbitals and atomic orbitals lies in the number of nuclei they are associated with. Here is a comparison table highlighting the differences between molecular and atomic orbitals:

Molecular orbitals are associated with the entire molecule and are created from the combination of atomic orbitals from different atoms. They can hold a maximum of two electrons of opposite spin per orbital and are filled from lowest energy to highest energy. On the other hand, atomic orbitals represent electron density in space associated with a particular atom and are characterized by quantum numbers.